Friday, June 7, 2013

One of the bewildering ironies of life in Utah is that although we live in the nation’s second driest state, many of us have access to unmetered water for our lawns and other summer irrigation needs. We pay a fixed (per acre) fee on our annual property tax bill, and then use as much or as little of the water as we like, from mid-April through mid-October.

Most of our secondary water systems are remnants of the agricultural irrigation systems that were here generations ago, when our suburban neighborhoods were still farms and orchards. I’m not sure why similar systems aren’t found in the suburbs of other Western cities, but it could be simply because our water sources are relatively close to our population centers, making our water infrastructure inherently less expensive. Or it could be due to peculiar laws and practices that grew out of Utah’s early Mormon settlements.

The obvious down-side of unmetered water is that people have no economic incentive to use less of it. So Utahns plant enormous green lawns as if they lived in Kentucky, and then give the grass even more water than it needs. Those who use little or no water end up subsidizing those who waste it.

But the lack of a meter has another disadvantage: It deprives us even of the knowledge of how much water we’re using. As a scientist and educator, I live by the principle that knowledge is inherently beneficial, even when it has no practical consequences.

So, of course, I found a way to measure my secondary water use. First I tried holding my lawn sprinkler over a bucket and measuring how long it took to fill. Then, for convenience, I bought a little $29 meter that screws into a hose line. After making just a couple of measurements I had a very good idea of how many gallons per minute were coming out of the hose, so from then on it was just a matter of timing how long the sprinklers were on and doing a bit of arithmetic.

Here are my results, from last summer’s watering season: I used 1900 gallons outdoors during June, 3200 gallons in July, 2500 in August, and 1600 in September. The total for the season was 9200 gallons, and about 90% of that went onto the patch of buffalo grass in my back yard. The rest was for spot-watering various trees, shrubs, and perennials. I tried to water about twice a week during the hot part of the summer, but sometimes it ended up being less, due to laziness or forgetfulness or being out of town.

For comparison, my indoor water use at home averages about 800 gallons per month.

About half of the city of Ogden—mostly the older neighborhoods—doesn’t have secondary water. Residents in those areas irrigate with metered culinary water, so we know how much they’re using. The amounts vary enormously, with many households using only a few thousand gallons per month but a few dozen customers using hundreds of thousands of gallons each. The use distribution from August 2012 is shown below, with the largest users (about 7% of them) omitted in order to show the rest at a reasonable scale. The median use among these customers during that month was 14,100 gallons, while the average, skewed by the high-use customers, was 20,500 gallons. One customer used a whopping 513,900 gallons.

These customers, of course, have a financial incentive to limit their water use (although thanks to relatively high base rates, the per-gallon fees aren’t very noticeable for those who use only a few thousand gallons per month). We can only presume that the other half of the city, with no such incentive, uses considerably more irrigation water per household.

For their culinary water, customers in Ogden receive a bill that shows not only the amount charged, but also the gallons used. In recent years the city has put additional useful information on the bill, such as the monthly amounts used over the past year (shown as a column graph) and a breakdown of how the water bill was calculated (which I personally lobbied for in early 2012). What’s still missing is any information comparing your usage to that of other city residents.

Along these lines, take eight minutes to watch this fantastic TED lecture. The speaker is Alex Laskey, president of a young company called Opower that helps utilities conserve energy by keeping their customers better informed. As Laskey describes, Opower’s work was motivated by an experiment done a decade ago in southern California, in which researchers found that the way to motivate people to use less electricity was to inform them about the conservation efforts of their neighbors.

Wouldn’t it be fantastic if all our utilities told customers how their usage compares to the average use of their neighbors? We could start with culinary water customers, right here in Ogden.

For our unmetered secondary water, though, it won’t be so easy. The first step is obviously to install meters. That will take a long time, but already the process has begun. Our area’s largest supplier of secondary water now has a pilot program to meter its customers’ usage in a few small neighborhoods. Based on the success of this program, I’m told that they’re hoping to install meters throughout their service area within as little as a decade. At that point they can, if they choose, begin to charge customers based on usage. But even before that controversial step, I suspect they’ll see significant water savings merely from telling customers whether their usage is excessive by local standards.